The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
Ion exchange materials are commonly employed to treat and remove ionizable components from fluids for a variety of applications. Flow-through beds or flow-through devices for fluid treatment may employ exchange material or components in the form of grains, fabrics or membranes. The ion exchange functionality operates to transport one type of ion across the material in an electric field, while substantially or effectively blocking most ions of the opposite polarity. Anion exchange polymers and materials carry cationic groups, which repel cations and are selective to anions. Cation exchange polymers and materials carry anionic groups, which repel anions and are selective to cations.
Ion exchange membranes may be prepared by polymerization of an ionic monomer, containing a cationic group for anion exchange membranes or an anionic group for cation exchange membranes, along with a crosslinking co-monomer in the presence of a backing of a stable reinforcing fabric, such as polypropylene, polyester, polyvinyl chloride, or polyethylene. The minimum thickness of the resulting ion exchange membrane is constricted by the fabric, whose thickness may be from 0.5-0.7 mm. Fabrics may be pre-treated with different chemicals to improve the wettability and compatibility with ion-exchange materials.